The Metropolitan Police have revealed that a man arrested outside Buckingham Palace on Friday night was brandishing a 4ft sword.

The 26-year-old, who was arrested for grievous bodily harm and assault on police, has been further arrested under the Terrorism Act 2000 as counter-terrorism police now lead the investigation.

As unarmed police challenged the man, who was sat in his car at the time, he reached for a four-foot sword which was in the front passenger foot well.

During the struggle to detain the suspect, three officers sustained minor injuries. The man, who repeatedly shouted Allahu Akbar, was incapacitated with CS spray.

Two of the officers were taken by ambulance to hospital with minor cuts and were discharged shortly after. The third officer did not require hospital treatment.

Dean Haydon, head of counter-terrorism at Scotland Yard, said: “I would like to pay tribute to the bravery and professionalism of these officers who quickly brought this incident under control. Their vigilance, courage and the swiftness of their response demonstrates how our officers are protecting the public at this time.

“Officers from the Counter Terrorism Command are now investigating and searches are being carried out in the Luton area today.

“We believe the man was acting alone and we are not looking for other suspects at this stage. While we cannot speculate on what the man was intending to do – this will be determined during the course of the investigation – it is only right that we investigate this as a terrorist incident at this time.”

Prime Minister Theresa May tweeted: “I want to thank the officers who acted quickly and bravely to protect the public last night demonstrating the dedication and professionalism of our police.”

No members of The Royal Family were in residence at Buckingham Palace during the incident. The Queen is currently at Balmoral Castle in Scotland for her summer break.

Anybody who witnessed the incident or has any information or images that may assist the investigation is urged to contact the confidential hotline on 0800 789 321.